Inyentor



Feb. 21, i956 l.. E. lammcHFLowER l 2,735,275

ICE MAKING MACHINE AND THE ART THEREOF l Filed Feb. 8. 1951 I5'Sh9etS-Sh99't l A v Y 7/ 60 g l zr I 60 'Il i 43 1 .Ly/e E. Eremo/flower 77'aR/vfY Feb. 2l, 1956 Filed Feb. 8.

L. E. BRANcHFLowER 2,735,275

ICE MAKING MACHINE AND THE ART THEREOF 5 Sheets-Sheet 2 ATTO 1PA/Y Feb.2l. 1956 L. E. BRANcHFLowER 2,735,275

ICE MAKING MACHINE AND THE ART THEREOF' Filed Feb. 8, 1951 5Sheets-Sheet 3 vIN V EN TOR.

gy/e E. rancf/ower fn/MW ATTORNEY Feb. 21. 1956 L. E.` BRANcHFLowl-:R2,735,275

ICE MAKINGMACHINE AND THE ART THEREOF Filed Feb. 8, 1951 5 Sheets-Sheet4 1N V EN TOR. L y/e E. Brdncf/o wer ATTORNEY Feb. 21, 1956 L. E.BRANcHr-'LowER 2,735,275

A ICE MAKING MACHINE AND THE ART THEREOF Filed Feb. 8. 1951 5sheets-sheet 5 )'NVENTOR. Lyle E. Brancf/owef ATTORNY United StatesPatent Oliice 2,735,275 Patented Feb. 2l, 1956 ICE MAKING MACHINE ANDTHE ART THEREOF Lyle E. Branchflower, Seattle, Wash. i

Application February 8, 1951, Serial No. 210,030

7 Claims. (Cl. 62--107) The present invention relates to ice makingmachines land the art thereof. In more particular the present inventionis concerned with the making of sub-cooled ice in ake form by freezing afilm of water on a rigid refrigerated surface and removing and breakingup from such surface the resulting thin sheet of dry ice.

Many of the prior art devices for making ice in small pieces orparticles have the disadvantage that they produce ice that is wet oreven in the form of slush. Such ice cannot be colder than 32 F. Such iceis difficult to handle and store as it freezes into a solid cake whenstored in refrigerated bunkers. It will not handle easily by screw orbelt conveyors. Naturally, such wet ice has a short storage life withoutrefrigeration as compared with ice which is dry, sub-cooled, that is icewhich is below 32 F. In many industries, a satisfactory ice must bebelow 10 F.

Many of the prior art devices feed water to the freezing surface from atank by the partial or total immersion of the surface in such tank. Thismeans that there is a large volume of water which does not progress thruthe machine. Fungi and bacteria may accumulate. This may lead tounsanitary conditions, and the added cost of the tank is an importantitem of cost in the construction of the machine.

Also, many of the prior art devices freeze the water on an externalsurface. This increases the vapor in the surrounding atmosphere which isoften undesirable. Further, such machines are difficult to insulate.

Some of the prior art machines for making sub-cooled ice use a flexiblebelt on which the ice is formed. While such machines are successful, thecare required in the manufacture and operation of such belts is animportant item of cost and maintenance.

A further item of disadvantage in many machines is the need forconveyors and/ or chutes for the transfer of the ice from therefrigerated surface to a storage bin.

In the removal of ice from a rigid refrigerated surface there have beendeveloped several methods and associated devices which are based uponthe concept of either scraping the ice from the surface as in:

Taylor, 2,080,639, May 18, 1937 Taylor, 2,280,320, April 2l, 1942 or thewedging of the ice from the surface as in:

Holden, 1,020,759, March 19, 1912 Short, 2,310,468, February 9, 1943Raver, 2,308,541, January 19, 1943 Raver, 2,344,922, March 21, 1944Raver, 2,431,278, November 18, 1947 Short and Raver wedge small piecesaway from the main sheet of ice. Taylor scrapes against the main icesheet. Holden wedges as in Short and Raver, or scores into the ice sheetwith parallel closely spaced score lines. The Short and Raver devicesrequire a rather close ternperature control of the ice and specialmaterial upon which to freeze the ice for satisfactory operation. Icewhich does not come free stays on the surface and builds up until acutter blade contacts it. InHolden, the scoring edges are so closetogether in opposition that theforce from one is directed against anadjacent one. This operation cannot be efficient as the scoring edgesare working against each other and the ice is crushed to fine particles.

Raver has the disadvantage of using a tank in which his drum rotates forsupplying water to the refrigerated drum surface. Taylor and Holden usevspray heads directed at various parts of the refrigerated surface butthey do not secure uniform and efficient coverage. .Short has a seriesof holes in the bottom tank for running water onto his refrigeratedsurface. These holes will cause streams of water to channel down acrossthe refrigerated surface. These channels may coalesce far down thesurface but will not` form a continuous sheet of water near the top ofhis-refrigerated surface. Holden and Taylor clearly disclose that theice cornes off their machinein a wet condi.

tion. From the construction shown by Short, it is doubtful that he canobtain a dry ice as excess water and ice would seem inevitably to bemixed in the outlet.

Raver in the later filed patents, Short, and Taylor have recognized theproblem of obtaining velocity to the `refrigerant over the heat transfersurface to increase the heat transfer, to prevent the formation of gaspockets, and to reduce the accumulation of oil on the heat transfersurfaces. However, all of the prior art devices have the defect thatvelocity is attained by a loss of ,head and by a singlepass of therefrigerant across the heat transfer surface. In these devices thevelocity lmust be controlled by the rate of evaporation of therefrigerant or much wet refrigerant must be returned to the compressioncycle. Further, such devices do not provide for efficient separation ofthe gas from the liquid. Separation must occur in the machine whichmeans that some of the heat transfer surface must be contacted by gasonly and not liquid refrigerant. This means a low rate of heat transferfor these gas contacted areas.

Further, for eticient heat transfer, the presence of oil on heattransfer surfaces must be avoided.

Having in mind the above and other defects of the prior art, it is anobject of the present invention to construct a machine that, will makesub-cooled, dry, ice in ake form.

A further object of the present invention is the provision of aconstruction that insures that the dry ice will not have water addedthereto.

Another object of the present invention is the construction of a machinethat can deliver ice ,to a storage bin without the use of chutes and/orconveyors.

A further object of the invention is the construction of a machine thatdoes not use a tank for the supply of water for freezing.

A further object is the construction of a machine which has its freezingsurface totally enclosed from the atmosphere and in which there cannotbe any direct conduction or radiation from ambient conditions to the icebeing formed.

A further object of the invention is the attainment of the objectsherein by the freezing of the ice on a rigid surface.

Another object is the removal of the ice from the refrigerated surfaceby the isolation of small sections of the ice and the removal of suchsections by a sweeping action in a manner that one section does notinterfere with another during its removal.

A further object of the present invention is the provision of an iceremoving sweep having a particular form.

Another object is the placing of the water on the refrigerated surfaceso that the entire surface is covered.

A further object is the construction of the heat transfer device so thatthere is a high velocity of refrigerant across the heat transfersurface.

Another obiect is the provision of a gas separator and liquid return forthe refrigerant.

Another object is -the provision of means for cycling liquid refrigerantacross the heat transfer surfaces without the passing of suchrefrigerant to the compression unit.

Another object is the provision of refrigerant cycling means to obtain ahigh refrigerant velocity across the heat transfer surfaces, and whichmeans operates as a com` bined thermosiphon and gas pump.

A further object is the provision of a gas separation space outside ofthe refrigerant evaporator.

Another object is the provision of means for preventing the admission ofoil to the evaporator.

Another object of the invention is the provision of a refrigerantprecooler that also operates as an oil eliminator.

'Ihe above mentioned defects of the prior art are remedied and theseobjects achieved by the construction of a machine in which there isformed a sheet of thin ice on the inner surface of a refrigeratedannular rigid sleeve. The axis of this sleeve is upright and the lowerend of the sleeve is open and in communication with an ice storage binso that ice when removed from the surface will fall directly into suchbin. Water is supplied to the upper edge of the sleeve surface by aseries of circumferentially spaced apart streams each of which has avelocity component tangential to the circumference of such surface. Iceis removed from the ice formation surface by a series of sweeps parallelto each other. all arranged parallel to the axis of the sleeve, andspaced a few thousandths of an inch from the surface. The sweeps travelin circular paths. Each sweep has a helically curved edge or anapproximation thereof, the radius of which is close to that of theradius of the cylindrical ice formation surface. The forward end of thissweep edge enters the ice sheet in the direction of travel of the sweepor almost so. A collection trough for excess water is arranged below thelower edge of the ice surface. Moving with the sweeps are shields thatprevent any of the falling ice from entering the collecting trough andprevent any excess water from entering the ice bin.

Exterior of and concentric of the sleeve on which ice is formed is anannular refrigerant chamber, or -evaporator chamber, which is floodedwith a liquid refrigerant. The chamber is divided by an annular baleinto two annular spaces that are in communication at the top and bottomof the spaces. The liquid level is maintained at or near the top of thebathe. Liquid and gas will rise in the inner, ascending, space andliquid alone ows downward in the outer, descending, space.V Gas andentrained liquid are carried out of the top of the annular space to agas separator from which' the liquid returns to the outer annular spaceand the gas goes to a compressor.

The incoming refrigerant is expanded before reaching the evaporator andplaced in heat exchange relationship with theincoming high pressurerefrigerant to precool the refrigerant, and to condense and tofacilitate removal of any oil that may be in the refrigerant.

Having thus briefly described a machine embodying the present invention,such is described in detail hereinafter and shown in the accompanyingdrawings in which:

Figure l is a perspective view of an assembled machine with partsthereof broken away.

Figure 2 is a sectional elevation view on the diameter of the machine.

Figure 3 is a plan view of the device shown in Figure l.

Figure 4 is a transverse sectional plan view on the line 4--4 of Figure2.

Figure 5 is a transverse sectional plan view on the line 5-5 of Figure2.

Figure 6 is a plan view of the water feed ring.

Figure 7 is an enlarged view of a portion of the ring shown in Figure 6.

Figure 8 is a section on the line 8 8 of Figure 7.

Figure 9 is a detail view in perspective of two of the ice sweeps.

Figure 10 is a detail view in of the doctor blade and guard.

Figure 1l is a detail view in perspective of the top edge scraper.

Figure l2 is a detail view in perspective of the bottom edge scraper andthe water trough guard.

In the accompanying drawings, there is shown in Figure l a perspectiveview of an assembled flake ice machine. Parts of the machine are shownbroken away for clarity of understanding. vIn this view there is shownthe ice making machine mounted on the top of an ice storage bin 2 (shownin part only). The machine has as its principal parts a refrigerantprecooler and oil eliminator 3, a gas separation chamber 4, an annularevaporator 5, a base ring assembly 6, a lop ring assembly 7, and a rotorassembly 8.

perspective of a portion Evaporator The evaporator iscomposed of anupright inner cylindrical shell 10 upon the inner, or ice making surfacell, on which is formed the thin sheet of ice to be removed therefrom inthe form'o'f small flakes; an outer shell l2 concentric of the innershell and spaced outwardly therefrom; a top end closure annulus 13; abottom end closure annulus 14; and between said shells an annularcirculation baille l5 that extends circumferentially and longitudinallyof the annular evaporation chamber formed by said shells and end annuli,or rings, but is spaced from the ends and shells. The present evaporatoris to be operated in a flooded condition with the refrigerant 16,preferably ammonia, flooding over the top of the circulation baille 15.Refrigerant is delivered from the precooler 3 to the interior of theevaporator by way -of the separator 4 thru a refrigerant inlet opening17 formed in the lower part of the separator 4 and refrigerant isremoved from the evaporator to the separator 4 thru a refrigerant outletopening 18 formed in the outer shell 12 adjacent the top edge thereof.An inlet opening 20 is provided in the shell 12 for the return of liquidrefrigerant from the separator 4. In actual use the outside of the outershell 12 is covered with insulation which has not beenshown in thedrawings as such would only confuse the showing thereof. Also, inactualuse, the pre-cooler and the separator would be covered with in-'sulation.

Top and bottom rings The evaporator is set on the base ring 6 thatcarries on its interior and circumferentially thereof a water troughthat opens upwardly and i'sformed by the outer trough and base ring 21,the inner trough ring 22 spaced inwardly from the outer ring, and thetrough bottom annulus 23. The inner ring 22 has a slightly smallerdiameter than the inner shell 11) of the evaporator. Water collects inthe trough from the excess water running off the lower edge of the icemaking surface 11 and from overflow from the water feed overflowchamber. Water in the trough is drained therefrom thru trough drainopening 24 formed in the outer ring 21. Spider arms 25, 26 are securedradially of the rings 21, 22 to support at the axis of the evaporator aradialthrust bearing 27.

Set on the evaporator is a top ring assembly 7 that is composed of thecylindrical ring 28 that has spider arms 29, 30, 31 secured radiallythereof to support at the axis of the evaporator a radial-thrust bearing32. The annular opening thru the top ring may be closed by fixed annularclosure plate 33 and removable ones similar to the xed ones but notshown in the drawings.

Rotor assembly ring assembly 7. This motor drives a pinion 41 thatmeshes with a gear 42 secured to and coaxial of a composite shaft havinga top section 43 to which the gear 42 is secured, and a bottom section44. In the present disclosure, in plan view, the shafthas counterclockrotation. Secured to the bottom section of the shaft are an upper and alower shaft arm 45, 46. These arms carry a sweep rail 47 that isrectangular in cross-section, that.

extends from the top edge to the lower edge of the evaporator and thatis placed close to the ice making surface 11 of the evaporator with itsside opposed to such surface.

Secured to the side of the rail in opposition to the ice freezingsurface are a series of sweeps 48. yEach sweep (Figures 4 and 9) issomewhat in the form of a at plate having one edge secured to a sweepbase 48A fastened to the side of the rail 47 opposed to the ,ice surface11. Each sweep extends away from its base and the rail, andpast thetrailing edge of the rail. The trailing portion 49 of the sweep may besaid to have rake with respect to the rail 47. This trailing, or rake,portion has a sharp edge S0 in opposition to the freezing surface. Thisedge is obtained by beveling the top of the rake to leave or form theedge in the plane of the lower face of the rake. The sweep and this rakeedge are at a slight angle, about 4 to 5, to a plane normal to the axisof the freezing surface. In a machine in vwhich the radius of thefreezing surface is about two feet or more, the rake edge 50 may lie ina plane, but in smaller machines the edge would approach the form of aportion of a cylindrical helix whose diameter is that of the diameter ofthe freezing surface.

As a specific example, if the radius of the freezing surface is twentyinches, the rake edge 50 is two and onefourth inches long, lies in aplane, and is curved to a radius of twenty inches. The trailing end ofthe rake edge is seven thirty-seconds of an inch below the leading endof the edge. This slope of the rake edge sweeps the ice from the icesurface 11. The sweeps are spaced about one and one-half inches apart.All or most of the rake portion of the sweep trails the sweep rail. Thesweeps may be secured to the rail by welding, bolting, or keying.

The angle that the rake edge makes with a plane normal to the axis ofthe evaporator may be considered to be the angle of lead, or the lead,as in a screw thread. This angle, or lead, is critical as too great alead will cause the ice to powder and too small a lead will not effectsatisfactory ice removal as to quantity. Under proper shaping andlocation of the rake edge, and with dry ice about one-eighth toone-sixteenth inch thick, the ice removal at each passage of the sweepsis in the order of ninty-eight percent complete. Also, with this shapingof the rake and its edge, all the forces exerted on the ice by the sweepare parallel, or tangential, to the surface of the ice, except for suchforces as may result at the forward end of the rake edge where it entersthe ice. There is no force component where sweep and ice contact that isnormal to the ice freezing surface. Such a normal force causes the iceto powder along the rake edge with the result that forces are nottransmitted thru the ice for any distance sufficient to loosen the icebetween adjacent sweeps. This results in much or most of the ice beingleft on the freezing surface until a very thick layer is built up, asafter several passages Aof the sweeps.

Frost builds up on the end annuli 13, 14 and will extend inwardly beyondthe ice making surface 11. This frost is scraped back flush with thesurface 11 by upper and lower Scrapers 51 and 52 which are secured byarms to the upper and lower end, respectively, of the sweep rail, andwhich Scrapers have their scraping edges adjacent and overhanging theends of the freezing surface.

Also, carried at the lower end of the sweep rail is a trough guard S3that prevents ice falling from the sweeps from entering the troughformed in the base ring assembly 6. Any ice hitting the guard will bedeflected inside of the inner trough ring 22 and will fall into theWater system Water is delivered to the freezing surface 11 by a waterrecycle pipe 60 that empties into the uppervend of the hollow topsection 43 of the composite shaft. The lower end of this top section isclosed by a plug 61 which has extending therethru a short length ofoverow pipe 62 whose upper end is somewhat above the plug. Watercollecting above the plug is carried away thru nozzle ring pipes 63, 64to a nozzle ring 65 that is concentric of the evaporator, adjacent theupper edge of the freezing surface, and carried on nozzle ring arms 66secured to and radially of the upper end of the bottom section 44 of theshaft. The nozzle ring 65 is hollow, square in cross section and hasaround its lower outer edge` a series of orifices 67, or nozzles, thatare shaped to direct streams of water outwardly, downwardly, andcircumferentially in the direction of rotation and against the iceforming surface 11. This directing of the water against andcircumferentially of the ice forming surface spreads the water over thesurface and prevents its channeling. It, also, gives immediate coveragewith water at the top of the freezing surface. The nozzle ring issegmental for about 270 from immediately behind the doctor blade 54 andits guard 55. In this relationship, the doctor blade and guard preventwater from reaching the falling ice. The ninety degrees of the nozzlering that is open allows the ice time in which to dry and to be removed.The water delivered thru the ring is maintained constant by holding afixed pressure, or head, on the ring. This is accomplished by the use ofthe overflow pipe 62 and by maintaining during operation of the machinea flow thru the overflow-'to cornpensate for variations in the amount ofwater delivered to the top section 43. The overflow water passes thruthe overflow pipe 62 and into the top of the bottom section 44 where itis stopped by a plug 68. A drain pipe 69 leads from above the plug 68 t0the water collecting trough in the bottom ring 6. This drain pipe 69 issecured to the rotor assembly 8 and moves around with it.

Water from the collecting trough ows from the outlet 24 to a water sump70. Water from the sump is returned to the spray ring 65 by the feedpipe 60 in which is connected a water pump 71, driven by any suitablemeans. Make-up water is supplied from a water main 72 to the sump 70,and its flow into the sump is controlled by a water float valve 73.

Precooler-oil eliminator receiver of a compression system is deliveredthru a l supply pipe 81 to a heat exchanger where it is cooled betweenan outer jacket 82 and an inner jacket 83 thereof. These jackets may befinned in any suitable manner. The exchanger is located inside of thevessel 80. Refrigerant, cooled to near zero degrees Fahrenheit betweenthe iackets, passes thru the lowerI end of the heat exchanger and intothe bottom of the vessel where the viscous oil settles out. This oil maybe withdrawn thru the drain tube and valve 84 in the bottom of thevessel. Refrigerant is drawn olf the top of the vessel thru a pipe 85leading to an expansion valve 86 thru which the refrigerant is expandedto a lower pressure and returned by the pipe 85 to the inside of theinner jacket 83 of the heat exchanger. Passage thru the expansion valvereduces the temperature of the refrigerant so that in passing thru theexchanger it will cool the high pressure incoming gas. Liquidrefrigerant and gas from the exchanger is conducted to the separatorthru a pipe 87 connected between the exchanger and the inlet opening 17of the separator.

Separator i Gas and entrained liquid from the evaporator pass from thetop of the evaporator thru the outlet opening 18 to the gas separationchamber 4. The chamber is in the form of a closed upright separationtube 90 having an inlet 91 in the side near the bottom connecting withthe evaporator outlet 18, a liquid return opening 92 in the bottom ofthe separator connecting with the evaporator liquid return opening 20,and a gas outlet 93 in its side near the top which connects with thecompression system which has not been shown but may be of any standardand suitable type. The cross sectional free area of the separator tube90 is such that the rate of fall of the liquid particles in the gasstream rising in and thru the separation chamber will be greater thanthe upward velocity of such gas stream. A baffle 94 in front of theinlet 91 prevents short circuiting of the wet vapor from the evaporatorto the gas outlet 93 and gives the incoming vapor a helical movementwhich aids in the gas-liquid separation. Y

Operation In the operation of the present device, the motor 40 foroperation of the rotor assembly is energized to rotate the shaft 43, 44;water is supplied to the sump l0 from the water main 72, its level inthe sump is controlled by the iloat 73, and this water is circulatedover the ice making surface 11 by the circulating water pump 71 and itsassociated piping including the nozzle ring 65; refrigerant such asliquid ammonia is supplied from the high side of a compression system tothe precooler-eliminator 3, thence, thru the separator 4 to theevaporator 5, and the vapor from the evaporator has the entrained liquidseparated out in the separator 4 and returned to the compression system.

When the temperature of the freezing surface l1 falls to and below thefreezing point of water, ice will form on the surface. The open gap inthe water nozzle ring 65 provides a period during which water is notapplied to a portion of the ice surface which allows the ice to dry,harden, and sub-cool. This dry ice is swept from the freezing surface bythe sweeps 48 and cascades down along the doctor blade 54 and its guard55 to fall into the bin 2. Ice does not tend to lodge and pack betweenthe sweeps because the rake portion of the sweeps trails the rail uponwhich the sweeps are mounted. Ice is prevented from falling in the watertrough by the trough guard 53.

Oil is eliminated from the incoming refrigerant by being cooled andallowed to settlel out of the refrigerant in the precooler-eliminator 3.

A high rate of heat transfer is promoted by the rapid circulation of therefrigerant across the surface of the shell 10. This is accomplished bythe circulation baille 15 forming an ascending passage and a descendingpassage between the inner shell and the outer shell 12 of the evaporator5. Heat delivered to the refrigerant in the ascending passage and thegas formed in this passage induces an upward circulation of therefrigerant in the ascending passage and a downward'current in thedescending passage. Gas and entrained liquid arey drawn ol the top ofthe refrigerant adjacent the top end closure annulus 13 and the liquidremoved from the gas and l returned to the evaporator in the separator4.

The above construction gives a high rate of heat transfer and a largeoutput of ice per square foot of ice freezing surface. The ice is drywhen removed from the freezsaid inner surface so that water deposited onsaid surface will form into ice; watersupply means depositing water onsaid inner surface; a driven member coaxially mounted of and in saidcylinder; and a plurality of axially spaced apart ice removal bladescarried by said driven member, each having an outer ice engaging edgeportion disposedl generally in a horizontal plane, in close proximity tosaid inner surface, having the leading portion thereof disposed at ahigher elevation than the trailing portion and having a substantiallyllat and horizontal lower surface portion and an inclined upper surfaceportion which surfaces join to form an edge, whereby ice forming on saidinner surface is removed at a plurality of locations and movesdownwardly toward said open bottom of said cylindrical shell.

2. A ake ice maker and removing device comprising a vertical cylindricalshell member open at the bottom and having an inner surface;refrigerating means refrigeratinglsaid surface sothat water deposited onsaid surface will form into ice; a driven member coaxially mounted ofand in said cylinder; water supply means depositing water on saidsurface, said water supply means comprising a segmental circularreservoir carried by said driven member; and a plurality of axiallyspaced apart ice removing blades carried by said driven member anddisposed in alinement with the space between the end portions of thesegmental circular reservoir, each having an outer ice removing edgeportion disposed generally in a horizontal plane, and in close proximityto said surface, whereby ice forming on said surface is removedtherefrom at a plurality of locations. i

3. A flake ice maker and removing device comprising a verticalcylindrical shell member open at the bottom and having an inner surface;refrigerating means refrigerating the said inner surface so that waterdeposited thereon will form into ice; water supply means depositingwater on said inner surface; a driven member coaxially mounted of and insaid cylinder; a plurality of axially spaced apart ice removing bladescarried by said driven member, each having an outer arcuate ice engagingedge portion disposed generally in a horizontal plane, and in closeproximity to said'inner surface, whereby ice forming on said inner wallis removed at a plurality of locations; and a water collecting trough atthe lower'edge of said inner surface.

4. A machine for the manufacture of liake ice, comprising: a cylindricalshell having an inner surface adapted to be refrigerated; means forsupplying water to said surface so that ice in sheet form may be formedthereon; rotatable means arranged coaxially of said shell; base meansextending axially of and secured to said rotatable means; and axiallyspaced apart ice removing blades secured to said base means and eachextendingl toward and adjacent to said inner surface, each of saidblades being constructed and secured to said base means so that the sametrails said base means.

5. The combination set forth in claim 4 in which each of said blades isat an angle to its plane of rotation.

6. The combination set forth in claim 4 in which each of said blades hasa face normal to said surface, in which each of said blades has thisface at an angle to the plane of rotation of said blade, and in whichsaid face at said angle is forward of said blade during rotation.

7. A machine for the manufacture of ake ice, comprising: a cylindricalshell having an inner surface adapted to be refrigerated; means forsupplying water to said surface so that ice in sheet form may be formedthereon; rotatable means arranged coaxially of said shell; base meansextending axially of and secured to said rotatable means; axially spacedapart ice removing blades secured to said base means adjacent to saidinner surface, each of said blades having a face normal to said surface,and said face being at an angle to the plane of its rotation, and saidface at said angle being forward of said blade during rotation.

References Cited in the file of this patent UNITED STATES PATENTS 10Taylor Dec. 8, Taylor Ian. 5, Taylor May 18, Spiegl Oct. 21, Phelan Nov.1l. McClure July 7, Raver -s Jan. 19, Short Feb. 9, Phelan Aug. 7,Zwickl Mar. 15, Ecabert July 5, Swanson May 8, Walsh Nov. 20, LessardFeb. l2, Lessard Feb. 12, Nitsch May 20, Lees Nov. 17,

